Engraving-block.



' invirnnsrarns intense.

rarnivr onirica ,i

PERCY D. SHIRLEY, 0E ST. PAUL, MINNESOTA.

nivornavING-BLOCK.

To all whom t may concern.'

Be it known that I, PnRcY D. SHIRLEY, a citizen of the United States, and a resident of the city of St. Paul, county of Ramsey, and State of Minnesota, have invented a certain new and useful Improvement in Engraving-Blocks,` of which the following is a specification.

rIhis invention relates to a jewelers engraving block and has for its object to provide an improved device rof this character. The engraving blocks in use at the present time, after a short duration of use, have a i tendency to develop lateral or side play between their upper and lower halves. rlhe object of my invention therefore is to provide means for minimizing friction and wear between the movable parts of the block and preventing this undesirable lateral movement caused `by wear of these parts and which generally occurs after the block has been in use for a short time.

TNith these objects in view, I have devised the combination of parts hereinafter set forth and more particularly pointed out in the claims appended hereto.

For a more particular description of my invention, reference is to be had to the ac companying drawings, forming part hereof, in which;

Figure 1 is a vertical sectional view of an engraving block showing my improvements,

Fig. 2 is a plan view of the ball bearing which is interposed between the halves of the block; and

Fig. 3 is a sectional view on the line 3-3 of Fig. 2, looking in the direction of the arrows.

Throughout the various views of they drawing similar reference characters desig-y nate similar parts.

In the preferred embodiment of my invention as illustrated in the accompanying drawing, 1 indicates the usual semi-spherical lower half of the engraving block and 2 indicates the upper half which carries the jaws of the device `and which is adapted to rest upon the lower half l. The lower half l is provided with ra central recess 3 into which extends a central stud or spindle a formed on theiupper half 2 of the block.

` The upper half ofthe block has its under surface cut away or depressed as at 5 and l Specification; of Letters Patent. i

Patented oet. ic, i917'.

Application filed May 1, 1917. Serial No. 165,661.

the lower half has its upper surface correspondingly recessed as at 6 and these two depressions 5 and 6 form between them a space for the ball bearing, to be described.

rI`he ball bearing which is interposed between the halves of the block to minimize friction therebetween, has a central bushing 7 having an opening 8 through which the spindle e: extends, as shown.

A pair of spaced-apart plates `0r disks 9 are utilized to hold the balls l0,and these plates are held in spaced-apart relationship by the bushing 7 which has the shoulders 1l extending between the plates or disks 9. The edges ofthe faces on the bushing 7 are riveted as at l2 to secure the bushing to the plates and to securely hold the plates in position. The plates 9 are provided with a plurality of perforations 13 through which portions of the balls project and bear against the surfaces of the depressions 5 and 6.

Apertures 14C are provided in the plates 9 through which locking pin or screw, commonly used in engraving blocks, may pass, to lock the upper and lower halves of the block together.

It will be seen that I have provided a device having a minimum of parts and which is readily demountable when desired. The depressions as at 5 and 6 allow the two halves of the block to come very close together at their edges which prevents grease from the balls working out on the hands of the workman and also prevents dirt vand gravings from getting on the balls so that wear occurs.

In the drawing the space shown between the upper and lower halves and` between the various parts indicates merely a working fit but this space is shown greatly exaggerated for clearness.r

From the foregoing it is obvious that my invention is not restricted to the exact embodiinent herein shown, but is broad enough to cover all structures coming within the scope 0f the annexed claims.

I-Iaving described my invention what I claim is:

A device of the class described `comprising an engraving block having aniiipper half and a lower half, a recess in one of said halves, a spindle on the other half extending into said recess, the. halves of the block each having a depression, a ball bearing fitting resting on sadshoulders and openings in said depressions and interposed between the the plates through which the balls project halves of the block, said ball bearing having to bear against the halves of the block. 1@ a central bushing through Which the spindle Signed at the city of St. Pa'uhY county of 5 extends, shoulders on said bushing, a pair Ramsey, andA State of Minnesota, this 27th of plates surrounding f the bushing, said day oAprl,l 1917. f plates holding the balls between` them and Y PER-GY D. SHIRLEY.

Copies ,of this patent may' be obtained for ve cents each, by addressing the Commissioner of Patents,

`1- vWashington, D. C. v 

